Endoscopes are very expensive instruments which normally are not disposable. Therefore, they must be sterilized between uses on different patients to minimize the possibility of infection and the transmittal of disease. Currently, the only method of sterilizing is by soaking the endoscope in a disinfecting solution such as Cidex. While this solution renders the device essentially sterile, there is still some danger of transmitting disease utilizing soaking solutions.
Endoscopes as presently constructed, cannot be sterilized with heat because the heat causes the adhesive between the compound lenses in the endoscope to come apart. This is particularly true after repeated exposure to high temperatures. Of course, when these lenses fall apart the endoscope is useless and must be repaired or replaced.
Sterilizable or disposable sheaths have been provided on endoscopes which cannot be heat sterilizable as shown in my U.S. Pat. No. 4,878,485 and on cameras which cannot be heat sterilizable, as shown in my U.S. Pat. No. 4,914,521.
U.S. Pat. No. 3,592,199 to Ostensen discloses an autoclavable power pack unit for an endoscope in which a combination light source and power pack is autoclavable, including the lens. A tubular portion is mounted on a handle by a pair of clamping screws.
U.S. Pat. No. 4,590,923 to Watanabe discloses an arthroscope-video camera assembly that has a video camera enclosed in a stainless steel housing. The housing may be autoclavable for multiple procedures.
U.S. Pat. No. 4,646,723 to Arakawa et al. discloses an endoscope having a lens system. A heat conductive material is provided to permit heat accumulated in the lens system to be emitted to the outside.
U.S Pat. No. 4,745,471 to Takamura et al. discloses an endoscope in which lenses are separated from one another by an unspecified annular element and mounted in front of a solid-state chip.
U.S. Pat. No. 4,762,120 to Hussein discloses an endoscope with a handle that is threadably received in the body of the endoscope.
U.S. Pat. No. 4,832,003 to Yabe discloses an electronic endoscope tip having a spacer provided in the lens system.
U.S. Pat. No. 4,854,302 to Allred, III discloses a video equipped endoscope with a needle probe that has a CCD solid-state imager and a probe which is sterilizable, as by soaking. The probe includes a lens, a main rod, seal and fiber optic bundle.
U.S. Pat. No. 4,867,137 to Takahashi discloses an endoscope with lenses separated from one another by an unspecified annular element. The device uses a solid-state image sensor.
U.S. Pat. No. 4,971,035 to Ito discloses an endoscope having a CCD image sensor. A spacer is provided in the lens arrangement between the lenses.
While all of the foregoing devices are satisfactory for their intended purpose, none of them provide a heat sterilizable endoscope as suggested by the present invention.